In a cellular system, a cellular network generally tracks the location of a user equipment so that when an incoming call arrives, the cellular network is able to terminate the incoming call for the user equipment. When the user equipment moves from one routing area to another routing area of the cellular network, the user equipment sends a message to the cellular network to update the user equipment's location. This message is known as a route update message.
One popular technique to update a user equipment's location is distance based location update. In distance based location update, each cell of the cellular network broadcasts its latitude, longitude, and a parameter called a route update radius. In existing cellular networks, the route update radius is the same for all the user equipments in a particular cell. Each user equipment uses the broadcasted route update radius to calculate its routing area.
As a user equipment moves out of a routing area, it sends a route update message to the cellular network for updating its location. Upon receiving the route update message, the cellular network computes a new routing area for the user equipment. Having knowledge of the user equipment's routing area, the cellular network is able to alert the user equipment when there is an incoming communication for the user equipment.
When a number of user equipments are in one location, e.g. an arriving terminal of an airport, all of the user equipments in the location generally send route update messages at the same time. For example, after landing, many passengers switch on their user equipment at the same time and move together from immigration to baggage claim at the same time. Using distance based location update, because all the user equipments in the location send a route update message at the same time to the same cells of the cellular network, there is a burst of route update messages. A burst of route update messages places a burden on the cells of the cellular network and may also lead to additional traffic.
Accordingly, there is a need for a new method for updating location of the user equipment.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.